There is another problem with KMS for me. KMS breaks Xv on intel 855GM video (as in X40 thinkpad). The fix for that is to disable KMS in GRUB, and that fixes the backlight on resume problem too.
https://wiki.ubuntu.com/KarmicKoala/ReleaseNotes#No%20Xv%20support%20for%20Intel%2082852/855GM%20video%20chips%20with%20KMS
There is another problem with KMS for me. KMS breaks Xv on intel 855GM video (as in X40 thinkpad).
The fix for that is to disable KMS in GRUB, and that fixes the backlight on resume problem too.
https:/ /wiki.ubuntu. com/KarmicKoala /ReleaseNotes# No%20Xv% 20support% 20for%20Intel% 2082852/ 855GM%20video% 20chips% 20with% 20KMS